Recently, there has been increased research and development with respect to Radio Frequency Identification (“RFID”) device tags. These RFID tags essentially comprise small radio transceivers attached to a movable object. By coupling an RFID tag to an object, it has been the intent of developers of creating a system for tracking the whereabouts and identification of the object.
Several RFID systems have been developed. Generally, these designs have been relatively large in size—approximately cigarette package—and have been generally fabricated using hybrid circuit techniques. Besides their bulky size, the systems require the RFID tag to constantly remain activated.
Recently, there have been several breakthroughs in techniques in the design and manufacture of RFID tags. Examples of these include “Radio Frequency Identification Device (RFID) and Method of Manufacture, Including an Electrical Operating System and Method,” U.S. patent application Ser. No. 07/899,777, filed on Jun. 17, 1992, now abandoned; “Anti-Theft Method for Detecting The Unauthorized Opening of Containers and Baggage,” U.S. patent application Ser. No. 07/921,037, Jul. 24, 1992, now abandoned; “Electrically Powered Postage Stamp or Mailing or Shipping Label Operative with Radio Frequency (RF) Communications,” U.S. patent application Ser. No. 07/928,899, filed on Aug. 12, 1992; now abandoned; and “Modulated Spread Spectrum in RF Identification Systems Method,” U.S. patent application Ser. No. 08/032,384, filed on Mar. 17, 1993, now U.S. Pat. No. 5,539,775, all commonly assigned to Micron Semiconductor, Incorporated, and all incorporated herein by reference.
It has been thus a design criteria that these RFID tags be light weight and inexpensive. However, these systems previously have not addressed the need of low power consumption. Presently, RFID tags must be active to detect their location, as well as additional information. As such, there is a need to develop a RFID tag communications system having an active mode for receiving/transmitting data and a sleep mode for reducing power consumption.